We propose to determine the effect of zinc deficiency on dental caries susceptibility using rats as the experimental model. Zinc is important in bone mineralization yet few studies have investigated the role of zinc in tooth formation of dental caries. Thus, we propose to study the effects of a pre-eruptive zinc deficiency on teeth during the period of molar enamel formation. A zinc deficiency will be developed in newborn rat pups consuming milk inadequate in zinc from mothers fed a deficient diet. Appropriate control groups will also be included in the experimental design. All pups will be fed a cariogenic diet at weaning. After 14 days they will be sacrificed and the jaws scored for dental caries. Parameters to assess tooth mineralization will be zinc, calcium, and phosphorus concentrations. If we are able to establish that zinc inadequacy during enamel formation affects subsequent dental caries susceptibility, we propose to conduct studies on tooth chemistry and histology to investigate possible mechanisms. Also, we will determine if a zinc deficiency after tooth eruption influences dental caries susceptibility. We feel these studies will increase our understanding of the relationship between an aspect of malnutrition and dental caries susceptibility. Furthermore, these experiments may suggest more effective methods for the reduction or prevention of dental caries.